Seismic facies investigation of the late Cenozoic glacial history of Bransfield Basin, Antarctica

Author

Banfield, Laura Ann

Date

1994

Advisor

Anderson, John B.

Degree

Master of Arts

Abstract

Approximately 3000 km of high and intermediate resolution seismic data and 117 sediment cores were examined to reconstruct the late Cenozoic glacial history of Bransfield Basin, Antarctica. The complexity of a glacial setting requires seismic data with vertical resolutions of 20-30 m to adequately image the depositional environments. This study demonstrates the utility of higher resolution seismic records to develop a complete understanding of the complicated nature of glacial environments. Lower resolution data, while appropriate for studying larger-scale features, lack necessary detail and can lead to over-simplified models.
Investigation of the seismic facies resulted in characterization and mapping of glacial sub-environments leading to the construction of a subpolar depositional model for glacial-interglacial cycles. In addition, these results help constrain Pleistocene climatic conditions. As seismic facies analysis indicates no significant meltwater activity, it is suggested that temperate deglacial-interglacial conditions did not exist in Bransfield Basin during the time interval studied (Pleistocene? to present). Another outcome of this study was a 13,000-14,000 yr BP minimum age for the end of the last significant glacial period with $>$800 m of ice grounded in $>$600 m of water. Examination of the data and application of the depositional model led to identification of key sites for shallow and deep drilling to further resolve questions of timing and paleoclimate.